1. Field of the Invention
The invention relates to a fabrication method of a modification nano-array, and in particular to a fabrication method of a modifiable nano-array by embossing.
2. Description of the Related Art
Regular nano-structures having a diameter of about 100 nm has special functions, such as low-reflectivity of insect's ommateum, anti-adhering effect of inset's wing, lotus effect. In present nano-technology, the method of fabricating a polymer substrate with hydrophobic surface, anti-oil surface or low-reflective surface, comprises twice surface treatments, and is complicated and expensive. Using lithography as an example, the process of fabricating a surface with regular nano-structures is difficult and expensive as the nano-structures geometries scale down to 90 nm.
In Acta Physiol Scand, insect's ommateum with high-sensitiveness to light at night has been observed by C. G Bernhard et al (1962). Nano-structures of insect's ommateum having a diameter of less than 250 nm exhibit super-low reflectivity in wide wavelength range of light. Moth Eye Principle has been proposed in Nature (1973) by Clapham and Hutley. In Planta, Lotus effect has been observed by W. barthlott et al. There is a plurality of nano-protrusions having a diameter of less than 50 nm on the surface of lotus to obtain a self-cleaning surface due to small contact area of the nano-protrusions.
Using anodic alumina oxidation (AAO) as a template has been published in Science (2002) by M. Steinhard et al. The anodic alumina oxidation with a plurality of regular nano-holes is used to be a template for forming hollow polymer nano-tubes. In US published application (20030089899), Lieber et al provide nanometer-scale articles, including nanoscale wires which can be selectively doped at various locations and at various levels. In some cases, the articles may be single crystals. The nanoscale wires can be doped, for example, differentially along their length, or radially, and either in terms of identity of dopant, concentration of dopant, or both. In US published applications (2004/0126305), Chen et al provide methods of fabricating one-dimensional composite nano-fiber on a template membrane with porous array by chemical or physical process. The whole procedures are established under a base concept of “secondary template”. First of all, tubular first nano-fibers are grown up in the pores of the template membrane. Next, by using the hollow first nano-fibers as the secondary templates, second nano-fibers are produced therein. Finally, the template membrane is removed to obtain composite nano-fibers. In US published applications (20040013873), Wendorff et al provide porous fibers comprising a polymeric material. The fibers have a diameter of 20 nm to 4000 nm and pores in the form of channels extending at least to the core of said fiber and/or through said fiber. The process for producing the porous fiber comprises electrospinning a 5 to 20% by weight solution of at least one polymer in an organic solvent using an electric field above 10.sup.5 V/m to obtain a fiber having a diameter of 20 nm to 4000 nm and pores in the form of channels extending at least to the core of said fiber and/or through said fiber. The porous fiber may be used as a carrier for a catalyst, as an adsorbent or absorbent or as a biomaterial, may be chemically modified or functionalized or may be used as a template for producing highly porous solids. In above-mentioned patents, the template with a plurality of nano-holes must be removed by etching after the formation of the nano-tubes or nano-fibers in the nano-holes.
In korea Patent (Pat. No. KR20030084279), Woo Lee et al provide a method of fabricating nano-structures by AAO templates with different sizes of nano-holes or by a twice anodic alumina oxidation template. In this fabricating process, polymer dissolved in an organic solvent fills the nano-holes of the AAO template, and removing the organic solvent after the nano-holes is filled with polymer. After consolidation of polymer in the nano-holes, the template must be removed by etching to reveal nano-structures formed by the nano-holes. During the etching process, the nano-structures would be deformed and lose the shape of the nano-hole.
In Germany Patent (Pat. No. DE10154756) Sawitowski Thomas uses an oxide coating as a template to have an embossing process for forming nano-columns. In this fabricating process, the shape of the nano-columns cannot change with different process conditions, and the nano-columns are too weak to demolding without surface treatment.